The 10-year lease is for approximately 16,500 square feet, said Ehud Elizur, president of PBC USA Real Estate LLC, the building’s landlord. The deal was first reported yesterday by the New York Post.

Mr. Elizur declined to disclose financial terms of the deal citing confidentiality but did say asking rents on similar floors were in the mid-80s per square foot. The lease was signed February 1, 2013, Mr. Elizur said.

Tenants at 452 Fifth Avenue take each floor as core and shell and design the space to meet their requirements, said Mr. Elizur. Depending on the length of time it takes to design the space, KLS Diversified could occupy their new space within four to six months, he added.

Now that KLS Diversified has inked its lease, all that remains is a 2,500-square-foot pre-built space, Mr. Elizur said. Three more floors will be released to the market in the coming months once an elevator project is completed, he added.

The building is appealing to financial firms, according to Mr. Elizur. “Firms such as KLS-and we have other similar firms-are looking for an environment where they can operate 24/7,” he said. “Usually financial firms want to be able to work earlier and stay later, and work weekends if necessary.”

Tenants are attracted to the fact the building has enough emergency power to operate cooler towers for both computers and the working space, Mr. Elizur said. “If you can’t air condition the work environment, no one can work there,” he noted. “We have ample emergency power to allow the whole system to operate.”

The building’s location is also a draw. The Midtown location provides close proximity to transportation hubs at Grand Central Station, Penn Station and Port Authority Bus Terminal, Mr. Elizur added.

The building was acquired from HSBC by PBC Real Estate, a subsidiary of Israel-based business group IDB Group, in 2009. The reported price of the building was $330 million. The British bank decided to sell their corporate headquarters in New York and other cities to increase equity, Mr. Elizur said. HSBC remains a major tenant in the building.

KLS Diversified was represented by Jones Lang LaSalle and Newmark Grubb Knight Frank, according to the New York Post report. The landlord was represented in-house and by CBRE through James C. Ackerson, Howard Fiddle, Zachary Freeman and Craig Reicher.

Calls to representatives for the tenant were not immediately returned.